GB1228539A - - Google Patents

Abstract

1,228,539. Electromagnets; electromagnetic switches. ROBERT BOSCH G.m.b.H. 7 Oct., 1969 [8 Oct., 1968], No. 49213/69. Headings H1N and H1P. A longitudinal stepping mechanism for a control rod 40 operating hydraulic valves regulating pressures in plural lines (Fig. 1, not shown) comprises axial electromagnet windings 17, 18 (Fig. 2) energized from an electronic control unit (not shown) mounted on a sleeve assembly 19 comprising brass bushes 20 separated by iron ring 21 within which an armature 22 is slidable (Fig. 3), and which is press-fitted to iron disc 23 separating the windings. The latter are enclosed in a metal housing 24, and iron bodies 26, 29 are enclosed therein having cores 28, 30 extending inwardly of the windings and supporting sleeve element 19; the disc 23 being engaged by the housing and fixed by inset 31 engaging groove 32. Each end of the armature is fitted with an axial collar (Fig. 4, not shown) engaging a mushroom headed extension 34 of cores 28 or 30 in each extreme position, and helical springs 35 engaging the cores and the armature centre, the latter when the coils are de-energized. The rod 40 of non-magnetic steel is a loose fit in bores of the armature and the cores, and is grooved annularly at 43 in groups at each end for locking engagement with pairs of pawls 42 pivotally located in radial slots (41) at each end of the armature (Figs. 4, 5, not shown) and aligned longitudinal grooves (44) on the armature periphery locate pivoted leafsprings 45 biasing the pawls, while oblique ended strips 48 inserted in ring 21 engage the longitudinal grooves of the armature to prevent rotation and also to engage and to disengage the appropriate pawls in and out of a locking position on the rod when the armature is displaced by engagement of either coil. The rod is accordingly displaced in either direction one step at a time and retained in its assumed postion by a spring-loaded ball lock 50, 52 engaging grooves 53. Plural insulated contacts 57 bracketed to body 29 are engaged by spring- loaded two-contact plate 61 carried by rod 40, to switch circuits of the electronic control unit in response to rod position. Non-magnetic bolts 64 passing through bores of the body 29 engage the armature 22 and carry insulated contacts 67 resiliently engaging others of contacts 57 switchably indicating armature position to the control unit, and a tongue 70 engaging a groove of shaft 40 prevents rotation. With rod 40 in extreme L.H. position, a current impulse to windings 17 draws armature to abut core 28, and R.H. pawls 42 carry rod 40 to the right by one step, while the L.H. pawls are disengaged. Contacts 57, 66 signal armature position to the control unit, which de-energizes winding 17 so that the armature recentres with disengagement of the pawls. The rod 40 is displaced further to the right or thereafter to the left by similar operations involving energization of coil 17 or coil 18. The armature may be magnetically polarized, and the windings energized to produce opposed magnetic fields.